1. Abrade the surface of the metal lightly with a 30 grit 3M Bristle disc or Scotchbrite pad.2.
Heat the raw brass slowly with an oxidizing flame (for a butane torch,
keep the end of the flame about 1 inch away from the surface of the
metal). Heat slowly to build up oxidation. Air cool or quench in water
and dry. 3. Remove the oxidation from the high spots by buffing
lightly with a coarse Scotchbrite pad or wheel, or use a steel scratch
brush.